javascript - Difference between angular.merge and angular.extend? -

can 1 please explain me difference between angular.merge , angular.extend..and deep copy means , when should used ?

extend : shallow copy properties of source objects right left, way destination object.

example: extend person , job objects , vise versa.

       //------------------------------------extend--------------------------          $scope.extendpersontojob = function () {            var person = { 'name': 'monica', 'age': '25', 'skills': { 'name': 'travelling', 'place': 'queenstown' } };             var job = { 'title': 'programmer', 'experience': '5',   'skills': { 'name': 'designing', 'experience': '2', 'certified': 'true' } };             // extend person job              $scope.persontojob = angular.extend(person, job);              //output : {{ 'name': 'monica', 'age': '25', 'skills': { 'name': 'designing', 'experience': '2', 'certified': 'true' } , 'title': 'programmer', 'experience': '5'}                      }          $scope.extendjobtoperson = function () {             var person = { 'name': 'monica', 'age': '25', 'skills': { 'name': 'travelling', 'place': 'queenstown' } };             var job = { 'title': 'programmer', 'experience': '5', 'skills': { 'name': 'designing', 'experience': '2', 'certified': 'true' } };              // extend job person             $scope.jobtoperson = angular.extend(job, person)            //output : {{ 'name': 'monica', 'age': '25', 'skills': { 'name': 'travelling' , 'place': 'queenstown' }  , 'title': 'programmer', 'experience': '5'}                       } 

merge deep (recursively) copy properties of source objects destination object.

example: merge person , job objects , vise versa.

    //------------------------------------merge------------------------------         $scope.mergepersontojob = function () {              var person = { 'name': 'monica', 'age': '25', 'skills': { 'name': 'travelling', 'place': 'queenstown' } };             var job = { 'title': 'programmer', 'experience': '5', 'skills': { 'name': 'designing', 'experience': '2', 'certified': 'true' } };             // merge person job              $scope.persontojob = angular.merge(person, job);              //output : { 'name': 'monica', 'age': '25', 'skills': { 'name': 'designing', 'experience': '2', 'certified': 'true', 'place': 'queenstown' }, 'title': 'programmer', 'experience': '5' };         }          $scope.mergejobtoperson = function () {             var person = { 'name': 'monica', 'age': '25', 'skills': { 'name': 'travelling', 'place': 'queenstown' } };             var job = { 'title': 'programmer', 'experience': '5', 'skills': { 'name': 'designing', 'experience': '2', 'certified': 'true' } };              // merge job person             $scope.jobtoperson = angular.merge(job, person)              //  //output : { 'name': 'monica', 'age': '25', 'skills': { 'name': 'travelling', 'experience': '2', 'certified': 'true', 'place': 'queenstown' }, 'title': 'programmer', 'experience': '5' };         } 

have example , compare better understanding. please correct me if wrong.

pc : david cai's blog